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How Do Drugs Work?

The Wales Drug & Alcohol Helpline, also known as DAN 24/7 is hosted by the Betsi Cadwaladr University Health Board with funding provided by the Welsh Government.

DAN 24/7 provides a free and bilingual telephone helpline providing a single point of contact for anyone in Wales wanting further information or help relating to drugs or alcohol. Anything you tell DAN 24/7 or any agency you contact is confidential and you won't even need to give your real name.

DAN 24/7 also provides a clear layout on drugs and alcohol, and their effects some of which can be found below:

How Do Drugs Work?

Drugs provide their effects by altering the way in which the central nervous system (CNS) operates. The CNS is the brain and spinal cord. The effects fall into one of three broad categories of depressant, stimulant or hallucinogenic.

 - Depressants

Slow down mental activity and physical functions, such as heart rate and breathing. They produce feelings of warmth and relaxation. Examples of Depressant drugs are Alcohol, tranquillisers, Heroin and the Opiates.

 - Stimulants

These drugs have the opposite effect of speeding up mental activity and physical functions, producing feelings of excitement and confidence. Examples of Stimulant drugs are NicotineCaffeineCocaine and Amphetamines.

Both types of drug can also produce feelings of euphoria, a mood of wellbeing and great contentment.

 - Hallucinogenic

On the other hand, usually have little effect on physical functions, as they work directly on those parts of the brain which control how the senses operate. They can alter the way in which the individual drug user perceives both their inner and outer worlds. LSD is an example of a Psychedelic drug.

Drug, Set and Setting

How these effects show themselves and how the drug feels to the individual is the result of a complex interaction between the properties of the substance itself (drug), the individual drug taker's mood, experience and expectations (set), and the environment within which the drug is taken (setting).

This trinity was first described by the American psychologist, Norman Zinberg, in his book 'Drug, Set and Setting', and provides a useful model to help in the understanding of drug use and the effects which drug users experience.


As the body becomes used to a drug, tolerance to the effects can build up. This means that increased doses are required to achieve the desired effect.


Some drugs, when used regularly over an extended period, can produce physical and/or psychological dependence or addiction.

Psychological dependence is an emotional craving for a drug to which the body has become accustomed. Physical dependence means the body has adapted to the drug and it is likely that withdrawal symptoms will follow when the drug is no longer taken.

Drugs with a potential for physical Dependence include the Opiates (HeroinMorphine, etc.), Opioids (synthetic opiate like drugs such as Methadone and Palfium), the Benzodiazepines - so called 'minor tranquillisers' (valium, librium, etc.) and Alcohol. There are also the Stimulant drugs with severe dependency potential. These include NicotineCocaineAmphetamines and Caffeine.

For more information:

Wales Drug and Alcohol Helpline

Freephone: 0808 808 2234

Or text DAN to: 81066